<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>密码可见案例</title>
    <style>
        .box {
            position: relative;
            width: 400px;
            border-bottom: 1px solid #ccc;
            margin: 100px auto;
        }
        
        .box input {
            width: 370px;
            height: 30px;
            border: 0;
            outline: none;
        }
        
        .box img {
            position: absolute;
            top: 2px;
            right: 2px;
            width: 24px;
        }
    </style>
</head>
<body>
    <div class="box">
        <label for="">
            <img src="images/close.png" alt="" id="eye">
        </label>
        <input type="password" name="" id="pwd">
    </div>
        <script>
            var eye = document.getElementById('eye')
            var pwd = document.getElementById('pwd');
            var flag = 0; //为0时密码不可见

            eye.onclick = function() {
                if (flag == 0) {
                    //点击一次 密码可见 flag更改为1
                    eye.src = 'images/open.png';
                    pwd.type = 'text';
                    flag = 1;
                }
                else {
                    eye.src = 'images/close.png';
                    pwd.type = 'password';
                    flag = 0;
                }
            }
        </script>
</body>
</html>